A5017069267- Advanced Chemical Physics Studies
- Astrophysics and Star Formation Studies
- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Catalytic Processes in Materials Science
- Atmospheric chemistry and aerosols
- Ion-surface interactions and analysis
- Ionic liquids properties and applications
- Organic Electronics and Photovoltaics
- Carbon Nanotubes in Composites
- Fullerene Chemistry and Applications
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
Rio de Janeiro Federal Institute of Education, Science and Technology
2018-2025
Universidade Federal do Rio de Janeiro
2015-2019
Instituto de Física La Plata
2018
We report the interaction of anhydrous acetonitrile, CH3CN (ACN), and deuterated methanol, CD3OD (MeOD), in condensed crystalline phase by electron impact with 2.3 keV energy. Theoretical experimental investigations are focused on fragments aggregates formed as a result electron-stimulated ion desorption. Positively charged were collected using time-of-flight mass spectrometry (TOF-MS) temperature-programmed desorption based quadrupole spectroscopy (TPD). The structures clusters identified...
Non-thermal desorption by electron impact constitutes an important route which neutral and ionic fragments from simple nitrile-bearing ices may be delivered back to the gas-phase of astrophysical environments, contributing production more complex molecules.
In this work, we report a systematic search of metastable C6Hn2+ (n = 1-6) dications from electron impact time-of-flight measurements several benzene derivatives in combination with global minimum based on the genetic algorithm. Our theoretical calculations reveal that < 6) structures are completely different dication, featuring linear carbon chains and/or cyclopropenylium moieties. Experimentally, doubly charged species were investigated for wide range energies, 20 to 2000 eV, and...
The desorption process induced by photons, electrons, or ions onto icy surfaces is an important mechanism for leading neutral ionized molecular species to the gas phase in interstellar and circumstellar environments. In this work, we report results of high energy electron impact a condensed pyrimidine ice means electron-stimulated ion (ESID). Desorbed cations from surface were analyzed time-of-flight mass spectrometry (TOF-MS). most abundant desorbed are H+ H2+, although several other...
We report on single- and double-charge photofragment formation by synchrotron radiation, following C 1s core excitation ionization Cl 2p inner of chlorobenzene, C6H5Cl. From a comparison experimental near-edge X-ray absorption fine structure spectra theoretical ab initio calculations, the nature various shell transitions molecule pure atomic features were identified. To shed light normal Auger processes or at sites, we addressed induced ionic species formation. With energy resolved electron...
In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on surface ice-covered grains promoting ejection processed material to gas phase. We report positive and negative secondary ion emission pure CH3CN, C2H3CN i-C3H7CN ices due bombardment heavy ions (252Cf fission fragments), simulating incidence onto icy surfaces. The emitted each sample were analysed by time-of-flight mass spectrometry...
Ionization and fragmentation pathways induced by ionizing agents are key to understanding the formation of complex molecules in astrophysical environments. Acetonitrile (CH3CN), simplest organic nitrile, is an important molecule present interstellar medium. In this work, DFT MP2 calculations were performed order obtain low energy structures most relevant cations formed from electron-stimulated ion desorption CH3CN ices. Selected reaction spectroscopic properties also calculated. Our results...
We report on direct measurement of all major ion-fragments and cluster-ions formed during high-energy electron impact 2 keV gaseous condensed-phase pyridine. The the parent pyridine cation are discussed in groups according to number atoms from aromatic ring. ion yield distributions within these show significant shifts towards higher masses for condensed compared due hydrogen migration. A wide spectrum desorbed hydrogenated fragment-ions ionic clusters with up 320 u observed yields protonated...
An experimental and theoretical study of the photoinduced homolysis carbon-chlorine bond in an ice matrix chlorobenzene is presented. A condensed film has been grown situ near edge X-ray fine structure (NEXAFS) spectra were collected after exposing to a monochromatic photon beam centered at 2822 eV resonant excitation chlorine 2850 eV. The photoabsorption Cl 1s → σ* π* states measured hypothesis free radical coupling reactions was investigated via time-dependent density functional theory...
Methyl cyanide (CH3CN) is the simplest organic nitrile and it found in almost all astrophysical environments, including cometary comae, Titan's atmosphere interstellar medium (ISM), especially starforming regions hot cores. In this work, role of ion desorption caused by electron collisions onto a CH3CN ice discussed. New ionic species, clusters are produced, pointing to delivery more complex species from surfaces gas-phase ISM.
Ion desorption measurements induced by the impact of electrons onto pyridine and pyrimidine ices will be presented. The data reported here is relevance for chemical evolution models astrophysical objects.